1. Field of the Invention
The invention relates to a device for heating an annular surface zone of a threadlike object.
The field of the invention is in particular that of splicing optical fibers for connecting optical fibers together.
2. Description of the Prior Art
Splicing two optical fibers together consists in effecting a weld between the ends of these fibers, correctly cut, aligned and positioned face to face, for example in a V guide. By heating for a few fractions of a second at a temperature of 2000.degree. C., the ends are melted and welded together. The heat source may be of three types: an electric arc formed between two electrodes, possibly controlled by a gas plasma, a micro oxhydric blow-torch or a carbon dioxide (CO.sub.2) laser.
For heating an annular surface zone of a threadlike object, for example an optical fiber, which corresponds to the problem which the invention seeks to resolve, a heating zone must be obtained whose contours are defined with great accuracy, which was not the case with the devices of the prior art. In the rest of the specification, the example of a fiber will be more particularly considered.
The device of the invention allows pin-point melting of the fiber with very low laser powers. It further allows good symmetry of resolution of the heated zone to be obtained.